Pb、Zn、Cd和Cr等元素的生物有效性研究——以胶州湾水生系统为例

Bioavailability of Pb, Zn, Cd and Cr—Bioaccumulation in Clam from Aquatic Ecosystem in the Jiaozhou Bay

本文首先利用同站位多介质同采的资料分析研究了各环境介质中的不同痕量金属对生物富集的贡献,提出孔隙水中Pb、Zn、Cd、Cr对生物体中同名组分富集的贡献较大;进而采用PHREEQC软件模拟了孔隙水中Pb、Zn、Cd、Cr四种元素的组分存在形态,结果表明:PbCO3、Zn2+、CdCl2、Cr(OH)3分别为孔隙水中Pb、Zn、Cd、Cr的优势态,但其生物有效形态依次为PbSO4、ZnOHCl、CdCl+、Cr(OH)2+。最后作者提出生物对其所处环境介质中痕量金属的富集并不取决于痕量金属的总量或其相应的优势态浓度的多寡,而是取决于痕量金属的生物有效态的浓度大小。

In this aquatic ecosystem study, bottom water, sediments, pore water, and clam were sampled for trace metals analysis. The authors probed into the relationships of trace metals in aquatic ecosystems and the bioaccumulation of Pb, Zn, Cd and Cr in clam in relation to their respective concentrations in the pore water. Moreover, the speciation of Pb, Zn, Cd and Cr in the pore water was simulated by the software PHREEQC. The results reveal that PbCO-3, Zn 2+, CdCl-2 and Cr(OH)-3 are dominant species in the pore water. The bioavailable species, however, are PbSO-4, ZnOHCl, CdCl+ and Cr(OH)+-2. It is concluded that the trace metal bioaccumulations in aquatic ecosystems are essentially controlled by the concentrations of bioavailable species rather than by the total concentrations of trace metals or the contents of their dominant species.